For all the hype swirling around electric aviation, the current state of battery technology and electric powertrains remains a limiting factor for all the drones, air taxis, cargo haulers, and flying cars. A Florida-based startup is taking a different approach due to restrictions on the range, power, and speed of these aircraft. Thus, instead of relying on batteries and rotors, UAV Turbines have developed a tiny jet engine.
The Florida-based startup flew its first microturbine-based propulsion system, called Monarch 5 in August 2019. It was flown in a compact fixed-wing drone weighing about 500 pounds, with a 22-foot wingspan. This quiet jet engine can generate electricity for electric motors, power propellers, or even produce its own thrust. Even though pocket-sized jet engines have been boosting radio-controlled model airplanes for decades, the company calls the Monarch 5 the first commercial-grade microturbine.
“The small UAV market uses aircraft—typically 500 to 1,000 pounds—that are too small for real turbine engines but too large for just electric battery propulsion,” says CEO Kirk Warshaw. “As a result, they’re using motorcycle or even weed-whacker-type engines … Microturbine power can contribute to hybrid systems, generate significant power for vertical liftoff and landing.”
Jet engines—aka turbines—have long been renowned for their performance. Even with hundreds of passengers on board they can send fighter jets to supersonic speeds or airliners halfway around the globe. Jets have made impressive efficiency gains over many years, while the airline industry has come under scrutiny for its contribution to climate change.
The smallest turbines also can power a light business jet or serve as auxiliary power units in larger aircraft, starting the bigger engines and supplying electricity when parked at the gate. Even those are similar to the size of a small refrigerator and weigh several hundred pounds.
UAV Turbines was formed via a merger of three model plane companies eager to get into the then-nascent drone industry in 2000. “Modelers don’t need them to fly that long, so getting 20 hours from a single-engine is more than a year’s worth of flying,” says Fred Frigerio, a senior vice president and program manager.
The team designed one of the smallest commercial-grade variable pitch propellers, which is common on turboprops and regulates aircraft speed by altering the angles of the propeller blades and not rev the engine up or down. The result weighs just 80 pounds and is 18.5 inches long and 12 inches in diameter. It generates 200 horsepower and runs on standard jet fuel. According to Warsaw, it is beneficial to the military users especially in remote locations where electrical charging infrastructure doesn’t exist.
“It could serve as an electrical generator for radar or communications technologies, alleviating the wear and tear on diesel truck engines that typically power such hardware now. In fact, the company already has a contract with the Army to develop the technology for its unmanned systems”, he says.